A group of House Democrats said Tuesday they would rather defeat the entire farm bill than agree to food-stamp cuts that Republicans are proposing in the legislation, which is expected to see its first committee action Wednesday.

“Overall, this is about whether or not we will have a farm bill,” Rep. Rosa L. DeLauro, Connecticut Democrat, who worked on the last farm bill in 2008, told The Washington Times after a protest Tuesday morning just outside the Capitol. “I fought hard for food stamps and for the changes that we made. I’m not about to see it go backward.”

The farm bill, which must be renewed every five years, funds the government’s agricultural and crop-support programs, and also funds food stamps, whose use has grown dramatically in recent years. Given that growth, GOP lawmakers are eyeing food stamps as a program that could be trimmed amid deep deficits.

The Senate passed a bill last month that would end the direct farm payment system that most sides agree is a failure, and would replace it with a crop insurance program to pay farmers who incur losses.

The House bill also would do away with the direct payment system and replace it with a different crop insurance approach. But it goes much deeper in reducing food-stamp spending, slicing more than $16 billion during the lifetime of the bill.

The Democrats’ opposition to food-stamp cuts signals a tough road for the bill, which amounts to nearly $1 trillion in spending during the next decade.

Congress must submit a bill to President Obama by Sept. 30, or watch all farm bill appropriations revert to 1940 levels — the first version of the bill ever passed. Lawmakers have begun discussing a short-term extension of this deadline to allow more time for negotiations.

Democrats said the proposed cuts in the food-stamp funding, officially known as the Supplemental Nutrition Assistance Program, are a moral issue. They said as many as 3 million people could lose eligibility for food assistance, including roughly 280,000 children who receive school meals.

But Minnesota Rep. Collin C. Peterson, the ranking Democrat on the House Agriculture Committee, said last week the draft bill is a step in the right direction. The bill proposes $35 billion in total cuts over 10 years, compared with about $23 billion in the Senate version.

Mr. Peterson said over the weekend that he expects the cuts in food stamps to be reduced in negotiations before a final compromise bill emerges.